Preparation of basic polyvalent metal salts of organic sulfonic acids



United States Patent PREPARATION OF BASIC POLYVALENT METAL SALTS OF ORGANIC SULFONIC ACIDS Mathii'syan der Waarden and Johannes Marinus Hiirchner, Amsterdam, Netherlands, assignors to Shell Development Company, Erneryville, Calif., a corporation of Delaware No Drawing. Application January 29, 1954,

Serial N0. 407,173

Claims priority, application Netherlands February 17, 1953 .19 Claims. (Cl. 260-505 This invention relates to a method for preparing basic polyvalent metal salts of organic sulfonic acids. More specifically, it relates to the preparation of highly basic alkaline earth metal salts of alkylated aromatic sulfonic acids.

It is well known that when preparing a salt or soap of an organic sulfonic acid, the mere use of an excess of neutralizing agent, generally the oxide, carbonate, hydroxide, etc., of the desired metal, may result in a product which contains an amount of metal in excess of that theoretically required to replace the acidic hydrogens of the sultonic acid used as the starting material. For many uses, particularly as addition agents for lubricants, desirable results are obtained by the use of these so-called basic salts or soaps. The alkalinity of these products, in addition to improving the detergent properties of the oil, imparts the further characteristic of increasing what has been called the.alkaline reserve of the oil. Alkalinity of lubricating oils is of interest for decreasing wear of piston rings and cylinders. This is believed to be accomplished by neutralization of sulfur acids formed from combustion of the fuel, which otherwise result in corrosive wear.

With the demonstrated superiority of such basic soaps over the normal or slightly acidic soaps, many attempts have been made to increase the basicity of the salts or soaps. Generally, the prior art processes involve the use of a large excess of neutralizing agent in a process more or less conventional for producing salts or soaps. However, it has been found that there is a definite upper limit to the amount of basic material which can be held in combination in these products prepared by conventional procedures.

It is a principal object of the present invention to provide an improved process for the preparation of basic salts of organic sulfonic acids. A more specific object is to provide an improved process for the preparation of basic divalent metal salts, especially alkaline earth metal salts, of alkylated aromatic sulfonic acids. Other objects and advantages will become apparent from the detailed description of the invention.

In accordance with the present invention, it has now been found that a polyvalent metal, particularly a divalent metal, organic sulfonate of relatively higher basicity can be prepared by reacting a polyvalent metal organic sulfonate of relatively lower basicity with an inorganic polyvalent metal salt apd with an alkali metal hydroxide in the presence of an aliphatic alcohol of from about 1 to about 3 carbon atoms.

Described in greater detail with respect to a preferred embodiment of the invention, the present process comprises gradually adding an alkali metal hydroxide in solution in water and/ or an aliphatic alcohol of from about 1 to about 3 carbon atoms to a solution of an alkaline earth metal 'alkylated aromatic sultonate of relatively lower basicity and an inorganic salt, preferably a water-soluble salt such as the chloride or bromide, of the corresponding alkaline earth metal in a solvent which comprises at least 25% by weight of an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby the basicity of the alkaline earth metal alkylated aromatic sulfonate starting material is substantially increased, and recovering the alkaline earth metal alkylated aromatic sulfonate of relatively higher basicity from the reaction mixture.

Neutral polyvalent metal organic sulfonates are particularly suitable starting materials. However, the present invention is also of utility for increasing the basicity of slightly basic polyvalent metal organic sulfonates.

The sulfonate starting material can be derived from organic sulfonic acids of various types. The sulfonic acids can be aliphatic, cycloaliphatic, hydroaromatic, aromatic, heterocyclic or of a mixed type. Examples of suitable sulfonic acids are alkyl sulfonic acids, such as amyl, octyl, lauryl and dodecyl sulfonic acids; the sulfonic acids of alkylated or non-alkylated aromatic hydrocarbons, such as benzenesulfonic acid, toluenesulfonic acid, naphthalenesulfonic acid, triisopropylnaphthalenesulfonic acid, polyamylnaphthalenesulfonic acids, diphenylsulfonic acids and sulfonic acids of aromatic hydrocarbons substituted by higher alkyl groups, that is, alkyl groups of from about 8 to about 18 carbon atoms; sulfonic acids of phenols which can be monocyclic as well as polycyclic and monohydric as well as polyhydric and which can also be substituted e which extracts may, if desired, be alkylated before sul-Q fonation by reacting them with olefins or alkyl chlorides,

by means of an alkylation catalyst; organic polysulfonic acids such as benzene disulfonic acid which may or may.

not be alkylated; and the like. The preferred sulfonate starting materials for use in the present invention are those derived from alkylated aromatic sulfonic acids in which the alkyl radical contains at least about 8 carbon atoms, for example, from about 8 to about 22 carbon atoms. These sulfonic acids are particularly suitable for the preparation of additives for lubricating oils.

In carrying out the process of the present invention, the polyvalent metal organic sulfonate starting material, together with an inorganic salt of the corresponding polyvalent metal, is dissolved in a solvent which comprises at least 25%, and preferably at least by weight of an aliphatic alcohol of from about 1 to about 3 carbon atoms. Isopropanol is a particularly suitable alcohol. Methanol or ethanol can also be employed, or mixtures of the foregoing alcohols can be employed. Water or a liquid hydrocarbon can be used in conjunction with the aliphatic alcohol solvent. Suitable liquid hydrocarbons are the lighter hydrocarbon oils, particularly hydrocarbons of 10 or less carbon atoms or mixtures thereof.

The hydrocarbons can be paratiinic, naphthenic or aromatic or they can be of a mixed type. Examples of suitable hydrocarbons are benzene, toluene, xylene, gasoline fractions, such as a gasoline fraction having a boiling range between about C. and about 80 C., and the like. Mixtures of such hydrocarbons with alcohols containing up to by weight of the hydrocarbon are suitable solvent media for use in the process of the present invention.

The inorganic polyvalent metal salt employed is preferably the chloride or the bromide. However, the nitrate is also suitable.

The polyvalent metal organic sulfonate starting material is generally present in the alcoholic solutionin a concentration of from about 1% to about 10% by weight. The inorganic polyvalent metal salt and the alkali metal hydroxide which is subsequently added are preferably employed in amounts in excess of that theoretically required to form a compound having the formula: [(RSO3)nM][M(OII)n], in which M represents the polyvalent metal, n represents its valency, and R represents an organic radical. In general, an excess of from about 25% to about 250%, particularly from about 25% to about 150%, calculated on this theoretically required quantity, is suitable. If-desired, larger quantities can be used.

The type of the solvent and of the inorganic salt of the polyvalent metal, as well as the quantities of the various components of the starting mixture to which the alkali metal hydroxide solution is gradually added, is selected in such a manner that the starting mixture forms a homogeneous solution. v

A solution of an alkali metal hydroxide in water and/ or an aliphatic alcohol of from about 1 to about 3 carbon atoms is then gradually added to the alcoholic solution of the polyvalent metal organic sulfonate starting material and inorganic polyvalent metal salt. The alkali metal hydroxide can be dissolved in the same alcohol as is present in the solution of the polyvalent metal organic sulfonate starting material, or a difierent aliphatic alcohol of 1 to 3 carbon atoms can be employed. The alkali metal hydroxide can also be dissolved in water or in a mixture of water and a suitable aliphatic alcohol. If the alkali metal hydroxide solutionis employedin aqueous solution, it is advisable to dissolve the sulfonate starting material and the inorganic polyvalent metaljs'alt in a solvent phase containing suflicient of the aliphatic alcohol of 1 to 3 carbon atoms that, after theaddition of the aqueous alkali metal hydroxidesolution, the reaction mixture contains at least about 25% by weight of the aliphatic alcohol, calculated on the solvent phase. Generally, a solution of sodium or potassium hydroxide in methanol or ethanol, either alone or in admixture with water, is very suitable.

The concentration of the alkali metal hydroxide solution is preferably from about 0.5 to about 5 normal.

The alkali metal hydroxide solution should be added very gradually to thesolution of the sulfonate starting material and inorganic polyvalent metal salt in order to prevent a local excess of the free hydroxide of the polyvalent metal from being formed and separating out from the solution as such instead of combining with the sulfonate to form the desired basic sulfonate. In general, a satisfactory yield of basic sulfonate can be obtained by adding the alkali metal hydroxide solution over a period of from about 1 minute to about 1 hour. It is further advisable to mix the alkali metal hydroxide as quickly as possible uniformly with the solution of the sulfonate starting material.

Upon the gradual addition of the alkali metal hydroxide solution to the solution of the sulfonate starting material and the inorganic polyvalent metal salt, the hydroxide of the polyvalent metal is formed by the reaction of the alkali metal hydroxide with the inorganic polyvalent metal salt, and the resulting polyvalent metal hydroxide combines with the sulfonate starting material to form the desired basic sulfonate.

The required conversion is promoted if the type and the quantity of the various components of the mixture to be converted are so selected that the alkali metal salt formed during conversion, such as an alkali metal chloride, precipitates from the solution.

In general, the basic sulfonate formed during the conversion is considerably 'less soluble in the solvents used than the starting sulfonate and, therefore, separates out from the solution. That quantity of the polyvalent metal hydroxide which is formed during the conversion and which does not combine with the starting sulfonate and the alkali metal salt which. is also formed during the conversion also separates out from the solution. The unconverted sulfonate starting material remains in solution.

In recovering the basic sulfonate product from the reaction mixture, the insoluble components are first separated from the reaction mixture, for example, by filtering or centrifuging. The basic sulfonate product is then extracted from the insoluble components by means of a suitable solvent. In general, light hydrocarbon oils are suitable for the extraction, particularly hydrocarbon oils with a final boiling point of not higher than about 300 C. The hydrocarbon oil can be aliphatic, naphthenic, aromatic or mixed base type. Hydrocarbons having 10 or less carbon atoms or mixtures of such hydrocarbons are especially suitable. Examples of suitable hydrocarbons are benzene, heptane, and gasoline fractions, such as a gasoline fraction having a boiling range of from about 60 C. to about C. If desired, the resulting extract can be concentrated by removing all or a portion of the solvent.

The solution containing the unconverted sulfo-nate starting material can be again subjected to the process of the present invention in order to produce further quantities of basic sulfonates.

By the above-described procedure, products having very high basicity can be obtained. In general, the products obtained contain at least as many hydroxyl groups as R503 groups. Hereinafter, the basicity of the product will be expressed as the ratio, in per cent, of hydroxyl groups to R803 group s.

If desired, the entire reaction mixture obtained by the process of the present invention can be worked to ob min as product a mixture of the relatively more basic polyvalent metal sulfonate produced in accordance with the present invention and the unconverted relatively less basic polyvalent metal sulfonate starting material. Such a mixture has very valuable properties, especially as a lubricating oil additive. Although the resulting mixture does not have as high a basicity as the relatively more highly basic sulfonate component alone, its basicity is still considerable, generally amounting to or more. To recover this mixture, the solvent is first removed from the entire reaction mixture, for example, by distillation, and the polyvalent metal sulfonates, that is the relatively more basic sulfonate produced by the reaction and the unconverted relatively less basic sulfonate, are extracted from the residue. Suitable solvents are the hydrocarbon oils described above with reference to the extraction of the relatively more basic polyvalent metal sulfonate alone.

If it is desirable toemploy the products obtained as lubricating oil additives in a form entirely free from the solvents used in the present process, this can be accomplished by incorporating the products in a lubricating oil fraction and expelling the solvents by distillation. In this manner, liquid concentrates can be prepared which can be added in minor amounts to the same or different lubricating oil fraction than that present in the concentrate.

Conversion of the polyvalent metal sulfonate starting material of relatively low basicity into a polyvalent metal sulfonate of relatively high basicity in accordance with the present process can be effected at room temperatures or somewhat elevated temperatures. Elevated temperatures are especially suitable when using concentrated solutions of sulfonate starting material since concentrated solutions are often very viscous and an increase in temperature results in a decrease in the viscosity of the solution. The temperatures employed will generally not be higher than the initial boiling point of the solvent at normal pressure.

The present process can be carried out either continuously or batchwise. When carrying out the process continuously, it is advisable to recycle a portion of the solu-.

tion withdrawn from the reaction zone. This has the advantage that the alkali metal hydroxide solution can be supplied more slowly than without recycling.

The process of the present invention can also be carried out utilizingas starting material a free sulfonic acid or an, alkali metal or ammonium salt :of a sulfonic acid. In 'suchz-cases, the freesulfonic acid or alkali metal or ammonium salt. thereof is converted to the corresponding polyvalent metal lsulfonate by reaction with an excess amount of an inorganic polyvalent :metal salt in the presenceof asolvent comprising at least about 25% by weight of an aliphatic alcohol of about 1 to about 3 carbon atoms as described above. The resulting solution containing polyvalent metal sulfonate and inorganic polyvalent metal salt is then reacted with a solution of 'suflicient alkali metal hydroxide to react with the inorganic polyvalent metalsalt to form a :polyvalent metal hydroxide which in turn combines with the polyvalent metalsulfonate present to form the desired basic sulfonate. Where a free sulfonic acid is used as the starting material, suflicient alkali metal hydroxide must be added also to neutralize the free inorganic acid formed in the conversion of the free sulfonic acid to its polyvalent metal salt.

The exact mechanism of the present process is not fully understood. Although the present invention does not depend on a theoretical explanation of the mechanism of the formation of the basic sulfonate, it is possible that the following occurs. The freehydroxide of the polyvalent metal is insoluble or only slightly soluble in the solvent used for the conversion. Extremely fine agglomerates are formed from'th molecules of the resultant free hydroxide of the ,polyvalent metal, and on their formation these agglomerates adsorb the sul-fonate start iug material. In this way, adsorption complexes are formed which are again compietely dispersible in hydrocarbnn oil and, consequently are very efiective lubricating oil additives. For the formation of these adsorption complexes it is essential toqallow the hydroxide of the polyvalentmetal tofiorminthe presence of the polyvalent metalsulfona'te. -:It is alsopossible that true basic sulfonates are formed; 1 i

If the organic sulfonic acid is represented by the formula RSOzH (:wherein'Ri represents an organic radical) and calcium is usedr-as;'a polyvalent metal, so that the. neutral sulfonate. is represented by (RSOahCa', while CaCla is used asaninorganic salt and NaOH as an alkali metal hydroxide," thetfonnafionfiof the basic sulfonate from theneut'ral sulfonate can be represented by the following equation:

The present invention is of particular utility for the preparation of highly basic sulfonates of divalent metals, particularly zinc and the alkaline earth metals, including magnesium. However, basic sulfonates of metals of higher valency, for example,'iron or chromium, can also be-prepared in accordance with the present process.

The invention is illustrated bythe following examples which are not to be construed as limiting the specification and claims in any manner:

,Example I The mixture obtained was then centrifuged, a ;soht-. tion of the neutral calcium sulfonate being separated as the liquid phase. .From the solid components consist ing-of a mixture of basic calcium sulfonate, calcium lay-.- droxide and sodium chloride, the basic sulfonatewa'sextracted by means of 50 :parts by weight of gasoline hav ing-aboiling range of60 C.- C.

On analysis it was found that the calcium sulfonate. dissolved in the gasoline had the very high basicity'of 328%. The yield of basic calcium sultonate amounted to 47% by weight of the theoretical yield.

Example 11 H A technical mixture of synthetic sulfoniciacids was prepared by alkylating and sul'fonating an aromatic extract having a boiling range of'180 C.275 C. (obtained by extracting a kerosene richfin aromatics W ith SOa). I The alkylation was canied'out by reacting '1 part by weight of the extract for minutes at 80 C. with 1' part by weight of a mixture otolefin's having 9-45 "carbon atoms (obtained by cracking paraftlin wax in the vapor phase) using 1.5% by weight of Al'Cl; (calculated on the whole mixture) as catalyst. The catalyst sludge was removed from the reaction mixture obtained.. during alkylation. The mixture was then treated with a 20% aqueous sodium hydroxide solution in order to neutralize the acid components present and then distilled to a boiling point of 300 C. in order to remove thelighter components which did not take part in the a'lkylag tion reaction. The residue thus obtained consisting of alkylation products with an average molecular weight of 470 was suifonate'd with 20%"by weight of oleum ata: temperature of 45 C. for a period of .90 minutes','after which the acid s'ludgeformedfwa'srernovedi 66.35 parts by weight of the lsulfoni cjacids tained, of which the acid number was 109, were in 90 parts by weight of isopropanol containi we'ight of water. ,In thesolution obtained 2 6"partsby weight of powdery calcium chloride (CaClaJZfiDTu/eref dissolved at 50-60 C. whil'efstirring od'erateTy. temperature of 50 -'60" TC. aud whi le shrring '62i5 p by weight of a 4.975 N solution of"'pdtassiu' hydro in 96% ethanol' were added to the solution. i of 20 rninutesf'l- The-,alcohtil whs then distilled from the reaction ture, f ter which the residue wasextracted with '1618 parts by weight of gasoline having a boiling range of 60 -80 C. The gasoline-insoluble components, viz. calcium hy droxide and sodium chloride, were separated from the solution of the sulfonates in the gasoline by centrifuging. In this way were separated 196 .parts'by weight of' a solution which contained 65 parts by weight of a. mixture of neutral and basic calcium sulfonates havingan average basicity of 136%. 1 This gasoline solution was mixed with 87 parts by weight of a Venezuelan lubricating oil rafiinate and, after exaporation of the gasoline, a product Wasobta ined 'consisting of 43% by weight of calicum sulfonates and 57% by weight of lubricating oil. This product could bek ept for a long time, :for instance, a month: or more, either at normal or increased temperature (e. g., C.) with-, out decrease of basicity. I

The highly basic polyvalent metal sulfonates preparedin accordance with the present process' are extremely suitable as lubricating oil additivesbecause. of their detergent properties andtheir anti-corrosive effect. They can be employed in lubricating oils in widely varying. concentrations, generally being employed in concentrations between about 0.1% and about 15% by weight. The sulfonates can also be combined with other lubricating oil additives, for example, antioxidants and extreme pressure dopes.

The present highly basic sulfonates may also advan tageously be used in other hydrocarbons. For example,

they are suitable for use in fuel oils where they counteract clogging of apparatus in which fuel oils are used. The present sulfonates can also be incorporated in light hydrocarbon mixtures such as those used as anticorrosives. Because of their surface-active properties, the sulfonates can also be used invpreparing emulsions of water and oil. The sulfonates can also be used in preparing lubricating greases.

We claim as our invention:

1. A method for preparing a highly basic alkaline earth metal alkylated aromatic sulfonate which comprises reacting an alkaline earth metal alkylated aromatic sulfonate with a hydrohalic acid salt of the corresponding alkaline earth metal and with an alkali metal hydroxide in the presence of a solvent comprising at least 25 by weight of an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted alkaline earth metal alkylated aromatic sulfonate and a solid phase containing a highly basic alkaline earth metal alkylated aromatic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic alkaline earth metal alkylated aromatic sulfonate, and separating the resulting hydrocarbon extract containing said highly basic alkaline earthmetal alkylated aromatic sulfonate from the extracted solid phase.

2. A method according to claim 1, wherein said"- 'ali-- phatic alcohol is isopropanol.

3. A method according to claim 1, wherein the alkaline earth metal is calcium.

4. The method of claim 1' wherein the said alkaline earth metal alkylated aromatic sulfonate is the basic sulfonate.

5. A method for preparing a highly basic alkaline earth metal organic sulfonate which comprises reacting an alkaline earth metal organic sulfonate with an alkaline earth metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted alkaline earth metal organic sulfonate and a solid phase containing a highly basic alkaline earth metal organic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic alkaline earth metal organic sulfonate, and separating the resulting hydrocarbon extract containing said highly basic alkaline earth metal organic sulfonate from the extracted solid phase.

6. The process of claim 5 wherein the alkaline earth metal organic sulfonate is an alkaline earth metal alkylated aromatic sulfonate and the said solvent for the reaction mixture comprises at least about 25 by weight of said aliphatic alcohol.

7. A method according to claim 5 wherein the said solvent comprises liquid hydrocarbon and said alcohol, the weight of the alcohol in said mixture being at least 25% by weight thereof.

8. A method for preparing a highly basic divalent metal organic sulfonate which comprises reacting a divalent metal organic sulfonate with a divalent metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted divalent metal organic sulfonate and a solid phase containing a highly basic divalent metal organic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic divalent metal organic sultonate, and separating the resulting hydrocarbon extract containing said highly basic divalent metal organic sulfonate from the extracted solid phase.

9. A method for preparing a highly basic polyvalent metal organic sulfonate which comprises reacting a poly valent metal organic sulfonate with a polyvalent metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted polyvalent metal organic sulfonate and a solid phase containing a highly basic polyvalent metal organic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic polyvalent metal organic sulfonate, and separating the resulting hydrocarbon extract containing said highly basic polyvalent metal organic sulfonate from the extracted solid phase. I

10. The process of claim 9 wherein the polyvalent metal organic sulfonate is formed in situ in the presence of the solvent by the reaction of a member of the class consisting of the organic sulfonic acids and alkali metal salts of such acids with a polyvalent metal salt of a hydrohalic acid.

11. A method for preparing basic alkaline earth metal alkylated aromatic sulfonates which comprises reacting an alkaline earth metal alkylated aromatic sulfonate with an alkaline earth metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising an aliphatic alcohol containing from 1 to about 3 carbon atoms, removing said solvent from the said reaction mixture, extracting the residue with a hydrocarbon solvent for alkaline earth metal alkylated aromatic sulfonates, and separating the resulting hydrocarbon extract containing said alkaline earth metal alkylated aromatic sulfonates from the extracted solid residue.

12. A method according to claim 11, wherein said aliphatic alcohol is isopropanol.

13. A method according to claim 11, wherein the alkaline earth metal is calcium.

14. A method according to claim 11, wherein the said solvent for the reaction mixture comprises at least 25 by weight of said aliphatic alcohol.

15. A' method according to claim 11 wherein the said solvent comprises a mixture of liquid hydrocarbon and said alcohol, the weight of the alcohol in said mixture being at least 25% by weight thereof.

16. A method for preparing basic alkaline earth metal alkylated aromatic sulfonates which comprises reacting an alkali metal alkylated aromatic sulfonate with an alkaline earth metal slat of hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising at least 25% by weight of an aliphatic alcohol containing from 1 to about 3 carbon atoms, removing said solvent from the said reaction mixture, extracting the residue with a hydrocarbon solvent for alkaline earth metal alkylated aromatic sulfonates, and separating the resulting hydrocarbon extract containing said alkaline earth metal alkylated aromatic sulfonates from the extracted solid residue.

17. A method for preparing basic alkaline earth metal alkylated aromatic sulfonates which comprises reacting an alkylated aromatic sulfonic acid with an alkaline earth metal salt of a hydrohalic acid and with an alkali metal hydroxide inthe presence of a solvent comprising at least 25 by weight of an aliphatic alcohol containing from 1 to about 3 carbon atoms, removing said solvent from the said reaction mixture, extracting the residue with a hydrocarbon solvent for alkaline earth metal alkylated aromatic sulfonates, and separating the resulting hydrocarbon extract containing said alkaline earth metal alkylated aromatic sulfonates from the extracted solid residue.

18. A method for preparing a highly basic alkaline earth metal alkylated aromatic sulfonat'e which comprises reacting an alkali metal alkylated aromatic sulfonate with an alkaline earth metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising at least 25 by weight of an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted alkaline earth metal alkylated aromatic sulfonate and a solid phase containing a highly basic alkaline earth metal alkylated aromatic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic alkaline earth metal alkylated aromatic sulfonate, and separating the resulting hydrocarbon extract containing said highly basic alkaline earth metal alkylated aromatic sulfonate from the extracted solid phase.

19. A method for preparing a highly basic alkaline earth metal alkylated aromatic sulfonate which comprises reacting an alkylated aromatic sulfonic acid with an alkaline earth metal salt of a hydrohalic acid and with an alkali metal hydroxide in the presence of a solvent comprising at least 25% by weight of an aliphatic alcohol of from about 1 to about 3 carbon atoms, whereby there is formed a liquid phase comprising said solvent and unconverted alkaline earth metal alkylated aromatic sulfonate and a solid phase containing a highly basic alkaline earth metal alkylated aromatic sulfonate, separating said phases, extracting the separated solid phase with a hydrocarbon solvent for said highly basic alkaline earth metal alkylated aromatic sulfonate, and separating the resulting hydrocarbon extract containing said highly basic alkaline earth metal alkylated aromatic sulfonate from the extracted solid phase.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,082 Zimmer et al. Jan. 29, 1949 2,585,520 Van Ess et al. Feb. 12, 1952 2,610,946 Eckert Sept. 16, 1952 2,671,758 Vinograd et al. Mar. 9, 1954 

1. A METHOD FOR PREPARING A HIGHLY BASIC ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE WHICH COMPRISES REACTING AN ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE WITH A HYDROHALIC ACID SALT OF THE CORRESPONDING ALKALINE EARTH METAL AND WITH AN ALKALI METAL HYDROXIDE IN THE PRESENCE OF A SOLVENT COMPRISING AT LEAST 25% BY WEIGHT OF AN ALIPHATIC ALCOHOL OF FROM ABOUT 1 TO ABOUT 3 CARBON ATOMS, WHEREBY THERE IS FORMED A LIQUID PHASE COMPRISING SAID SOLVENT AND UNCONVERTED ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE AND A SOLID PHASE CONTAINING A HIGHLY BASIC ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE, SEPARATING SAID PHASES, EXTRACTING THE SEPARATED SOLID PHASE WITH A HYDROCARBON SOLVENT FOR SAID HIGHLY BASIC ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE, AND SEPARATING THE RESULTING HYDROCARBON EXTRACT CONTAINING SAID HIGHLY BASIC ALKALINE EARTH METAL ALKYLATED AROMATIC SULFONATE FROM THE EXTRACTED SOLID PHASE. 